Many conventional pressure-side APCs utilize a flow of pressurized water to draw debris into a collection container. This result occurs because of the Venturi principle, as the pressurized water flow creates a low-pressure region drawing ambient, debris-laden pool water into a body of the cleaner. The debris-laden water usually passes through an opening in the bottom of the body and eventually through an opening in the bottom of a fluid-permeable bag (or other filter). Most solid debris remains in the bag while its carrying water exits because of the fluid-permeable nature of the bag. However, when the flow of pressurized water ceases, debris within the bag is susceptible to falling out of the bottom opening under influence of gravity.
Some jet nozzles through which pressurized water flows in these conventional cleaners usually are located inside a vacuum tube between the inlet thereof and the bag. Positioning the nozzles in this way facilitates drawing the debris-laden water into the tube. However, this positioning also increases risk of debris clogging the inlet to the vacuum tube, an undesirable result. Locating the jet nozzles within the vacuum tube additionally moves the low-pressure zone of the Venturi effect away from the to-be-cleaned surface of the pool, reducing effectiveness of the APC at drawing in debris and diminishing the suction force available to facilitate locomotion and climbing of the APC within the pool.
Furthermore, these jet nozzles typically aim the water flow through the center of the cleaner in a (mostly linear) direction perpendicular to the to-be-cleaned surface. Centrally locating the jet nozzles and vacuum tube, however, necessitates locating other components—including but not limited to the drive system, manifolds, and collection chamber(s)—at the perimeter of the APC. While this APC component lay-out is generally satisfactory, it is not always efficient.
Commonly-owned U.S. Pat. No. 6,601,255 to van der Meyden, et al., whose entire contents are incorporated herein by this reference, details another exemplary pressure-side APC. An illustrated version of the APC “is generally spheroidal in shape” and includes a central zone bounded by two rotatable segments. See van der Meyden, col. 6, ll. 35-38. Alternatively, the rotatable segments may be cylindrically shaped or resemble truncated cones. See id., col. 7, ll. 10-13.
As noted in the van der Meyden patent, debris-laden water may be ingested at the mouth of a curved suction (vacuum) passage and passed thereafter into a debris collector. Consistent with other pressure-side cleaners, those of the van der Meyden patent position jet nozzles within the curved suction passage. See id., col. 8, l. 45 to col. 9, l. 4. Also like other pressure-side APCs, those of the van der Meyden patent locate the suction passages in the central zones of the cleaners.